The present invention relates to packing machines in general, and more particularly to improvements in packing machines of the type wherein block-shaped or otherwise configurated commodities are draped into prefabricated blanks which are provided with score lines or fold lines to facilitate predictable and convenient folding of blanks around the respective commodities. More particularly, the invention relates to so-called wrap-around packing machines wherein discrete commodities or arrays consisting of groups of two or more commodities are draped into prefabricated blanks so that the blanks constitute envelopes which surround certain sides (preferably at least four sides) or all sides of the commodities. The thus obtained packages are then ready for stacking, storage or transport. As a rule, the blanks are drawn from a magazine and are transported to a packing station which receives commodities from a suitable conveyor. In many instances, the individual constituents of successive commodities are assembled into groups at or close to the packing station prior to placing of the thus obtained commodities onto the respective blanks which are thereupon draped around certain sides or all sides of the respective commodities. The overlapping portions of the blanks can be bonded to each other by resorting to an adhesive or in any other suitable way. The transporting system which delivers blanks from the magazine to the packing station is normally operated in stepwise fashion, preferably in synchronism with the conveyor or conveyors which supply commodities or individual constituents of commodities to the packing station.
In most instances, the magazine stores a stack of completely prefabricated blanks, i.e., blanks whose configuration and dimensions, as well as other characteristics, enable the instrumentalities at the packing station to convert such blanks into envelopes of predictable shape, normally into envelopes which closely hug the outlines of the respective commodities. This involves the application of weakened portions in the form of rows of perforations, score lines or the like so as to ensure that each and every blank of a long series of blanks will be folded and/or otherwise deformed in the same way as the preceding blanks.
If the packing machine is designed to process commodities whose dimensions vary sufficiently to warrant the manufacture of two or more sets of prefabricated blanks, the persons in charge must replace the previously used blanks with a new stack of blanks whenever the packing machine is to be converted from the processing of a first type of commodities to the processing of a different second type of commodities. For example, it is often necessary to make relatively low or relatively tall packages whose outlines are the same, i.e., the width and/or the length of the two types of packages remains unchanged but the height can differ slightly or to a considerable extent. In such instances, the manufactuer of blanks normally produces several types of blanks having identical fold lines for the regions of bottom parts of the various commodities and differently distributed fold lines for the upper parts of the various commodities. In other words, the fold lines which are to facilitate the folding of the top flaps or tucks of blanks are more distant from the fold lines at the bottom portions of envelopes for relatively tall commodities than the fold lines for the folding of top flaps and/or tucks of envelopes for relatively short or low commodities. By way of example, the bottom area of each of a long series of commodities may be a perfect one foot square but the height of a first batch of such long series may be in the range of 10 inches in contrast to the next-following batch of the same series whose height is 20 inches. Under such circumstances, the manufacturer of blanks must furnish two different types of prefabricated blanks whose overall dimensions need not necessarily deviate from each other but the distribution of certain fold lines is quite different. This contributes to the initial cost of the packages and necessitates relatively long interruptions of the packing operation during conversion from the processing of a first type of commodities to the processing of commodities of a different second type.